70
X. Feng et al.
Table 2.30 Asymmetric hydrosilylation of chromones and flavones 70
O
O
R
HB(C 6 F 5 ) 2 10
pentafluorostyrene
or chiral diyne 52a
PhMe 2 SiH
O
R
O
70
71
entry product
yield (%) ee (%)
1
71a
O
O
Me
98
21
2
71b
O
O
Et
91
17
3
71c
O
O
t Bu
95
32
4
71d
O
O
Ph
99
11
R
NH 2
NH 2
+ Ar
OR'
O
OR'
R
H
N
N
H
R'
PMHS, B(C 6 F 5 ) 3
one-pot tandem process
cyclization
deoxygentive
hydrosilylation
R
H
N
N
R'
R
H
N
N
H
R'
O
O
hydrosilylation
72
73
74
Scheme 2.19 Catalytic synthesis of 1,2,3,4-tetrahydroquinoxalines